Yep exactly! Setting up a raspberry pi low-performance computing cluster with secondary usb nics, going slowly insane trying to figure out why the vlan interfaces wouldn’t work when their base interfaces worked just fine, and going down all of the wrong rabbit holes along the way.

ifupdown2 has a 15-character interface name limit, and the systemd predictable interface naming system uses the mac address for usb nics (giving them a 15-character name), so if you try to create a vlan subinterface of a usb nic using the standard interface.vlan naming scheme on a systemd host, it will fail, and you’ll have to set up systemd network link files to rename the base interfaces to something shorter.

Yes, with the official M16A4 unit being defined as 1/100th the length between the goal lines of an American Football field.